brush is opaque. even though opacity, flow is 100%

[Tiboine]

here is one stroke with 100% black. opacity, flow, etc at 100%

layer is normal

the layer opacity is 100%

layer fill is 100%

but still, I have to brush 3-4 times to make it 100% black. 

I have reset preferences.

it's the latest Photoshop CC. 

this makes my job creating masks that require NO opacity very hard.

[c.pfaffenbichler]

Please post a meaningful screenshot that includes all pertinent Panels (Options Bar, Brush Settings Panel, Layers Panel etc.). 

[c.pfaffenbichler]

»this makes my job creating masks that require NO opacity very hard.«

What is a Mask without Opacity supposed to be exactly? Do you mean that the Masks should effectively be 1bit (so that each pixel is either fully solid or fully hidden)? 

[Tiboine]

sorry. the edges of the mask can't be opaque

"Do you mean that the Masks should effectively be 1bit (so that each pixel is either fully solid or fully hidden)? "

yes. 

[c.pfaffenbichler]

Then you should probably not be using the Brush Tool but the Pencil Tool. 

[Tiboine]

true. pencil worked out great. 

But it is still silly that brush tool doesn't fill 100% at small brush sizes. 

[c.pfaffenbichler]

What was the Brush’s Hardness? 

Please post a screenshot with the Brush Settings Pael visible.